I was looking through an older (early '70's) bee book. It suggested using 1/2 teaspoon of ammonium nitrate in a well lit, hot smoker to knock out a hot colony. The burning ammonium nitrate produces nitrous oxide & knocks out the colony for a while.
Have you heard of this? Does it work without killing too many bees?.
We usually just requeen a mean colony. That usually fixes the problem without too much loss of bees.